Shadow focus bug

Guys,

Is anyone else experiencing problems with Shadow Focus when coupled with vanish? I have video proof, through FRAPS, that shows when I pop vanish and vendetta together, I clearly receive the shadow focus buff however when I open with mutilate the move costs energy... strange.

I use the macro /cast vendetta /cast vanish and bind it to a single key. This "bug" is repeatable within the use of the macro (ie I have more than 1 video showing the same thing), but vanish on it's own seems to work just fine, utilising shadow focus correctly. One thing to note is that if I wait for a few seconds (at least a GCD) after using the macro the mutilate costs no energy, so I expect it could be me hammering mut too fast, but why I'm penalized for optimal playing I don't know...

Would anyone share any experiences or test this for themselves and let me know there results.